Conventionally proposed is a mold temperature control device (a mold temperature control system) having a high temperature medium supply portion for circularly supplying first medium, for example, high temperature medium, to a medium flow path of a mold and a low temperature medium supply portion for circularly supplying low temperature medium as the second medium having different temperature from that of first medium. Such a mold temperature control device is able to delay solidification of melted resin to be injected and charged in a mold cavity by heating the mold and to improve transcription ability (transcription rate) of the cavity surface to a molded product. In addition, melted resin is able to be swiftly solidified by cooling the mold after being charged, thereby shortening molding cycle.
In such a mold temperature control device, a mold heating mode circularly supplying high temperature medium is switched to a mold cooling mode circularly supplying low temperature medium. There has been such a problem that high temperature medium remaining in the medium flow path of the mold and in each path is returned to the low temperature medium supply portion, and the medium temperature in a storage portion of low temperature medium sharply rises. Thereby, it takes much time to drop the temperature of the medium in the low temperature medium supply portion to the predetermined temperature. In addition, when the above-mentioned mold cooling mode is switched to the above-mentioned mold heating mode, there has been such a problem that low temperature medium remaining in the medium flow path of the mold and in each path is returned to the high temperature medium supply portion, the medium temperature in a storage portion of low temperature medium sharply decreases. Thereby, it takes much time to raise the temperature of the high temperature medium supply portion to the predetermined temperature.
The Patent Literature 1 mentioned below proposes the heating/cooling device having the supply pipe line and the return pipe line connected to the heat medium path of the mold in which the cooling unit and the heating unit are connected to the supply pipe line and the return pipe line via the supply path, return path, and the circulation path, respectively. The heating/cooling device is designed such that the return pipe line is connected with the temporal water storage pipe having a pair of temporal heat medium tanks.
In the heating/cooling device, when hot water is switched to cold water, the return pipe line connected to the heat medium path of the mold is connected to the temporal storage tank, and hot water pushed out of the heat medium path of the mold by supplying cold water is supplied to the temporal storage tank. By supplying hot water, cold water previously stored in the temporal storage tank is pushed out and returned to the cold water circulation path via the cold water return path. On the other hand, when cold water is switched to hot water, the return pipe line connected to the heat medium path of the mold is connected to the temporal storage tank, and cold water pushed out of the heat medium path of the mold by supplying hot water is supplied to the temporal storage tank. By supplying cold water, hot water previously stored in the temporal storage tank is pushed out and returned to the hot water circulation path via the hot water return path.